Slotted tray for fractionating column and the like



May 20, 1969 v. BRAUN T L ,4

SLOTTED TRAY FOR FRACTIONATING COLUMN AND THE LIKE v Filed Oct. 11. 1967Sheet of 2 ,4' g Q 4 INVENTORS Masfimi/ 6/1700 W0 May 20, 1969 v, BRAUNET AL 3,445,095

SLOTTED TRAY FOR FRACTIONATING COLUMN AND THE LIKE Sheet of 2 Filed OGt.11, 1967 Zia 757701 grow; fi/a W526 INVENTORS United States Patent3,445,095 SLOITED TRAY FOR FRACTIONATIN-G COLUMN AND THE LIKE VlastimilBraun and Oto Vitek, Brno, Czechoslovakia,

assignors to CHEPOS, Zavody chemickho a potraviniifskho strojirenstvi,oborovy podnik, Brno, Czechoslovakia Filed Oct. 11, 1967, Ser. No.674,406 Int. Cl. B01d 3/22 U.S. Cl. 261114 6 Claims ABSTRACT OF THEDISCLOSURE In a fractionating column or similar contact apparatus inwhich a rising vaporous and/or gaseous phase countercurrently meets adescending liquid phase, there are slotted trays and caps for the slotsin the trays. The slots are elongated, and each cap which is formed andserves as a floating valve is to cover either a single slot or two ormore longitudinally aligned slots. Each of the caps is movable from andtoward the area of the respective tray, surrounding the respective slotor slots, and is centrally provided with lengthwise extending continuedrib means which depends from the underside of the cap downwardly towardthe respective slot or slots. The rib means is spacedly provided withmeans to engage the underside of the tray, when the respective cap movesupwardly, and thus to limit the upward movement of the cap.

Background of the invention This invention relates to a slotted tray forfractionating columns and the like, and is to effect intimate contactbetween rising vapors and/or gases and a heavier descending liquid. Thetray is provided with a plurality of elongated, ordinarily parallel,slots which are covered by elongated caps. A cap covers either a singleslot or two or more longitudinally aligned slots.

Such trays are particularly suitable in countercurrent operations inrectification, disillation, absorption columns and similar apparatus.

The primary object of this invention is to generally improve slottedtrays for fractionating columns and the like, to simplify and strengthentheir construction, to cheapen their manufacture, assembly, andmaintenance, and to render them more eflicient and reliable.

Important objects of our present invention center about a tray whichwill ensure even distribution of both the vaporous and/or gaseous phaseand the liquid phase for effective heat and intimate mass transfer andwill improve the efficiency of the tray, enhance the capacity of acolumn equipped with the tray of the invention, and achieve a wideflexibility of the column within a broad range of practical services.The invention aims at securing a more uniform efiiciency of the tray,and more intimate contact between the countercurrently moving twophases, across the whole tray surface.

One object of the invention is to ensure, along with a properdistribution of the liquid on the tray, a proper hydraulic balance andthus to substantially reduce the hydraulic gradient.

A further object of our invention is to provide a tray that is free ofobstructions to the liquid flow and will lessen sedimentation ofimpurities and the necessity for the provision of frequent cleaningintervals, especially in services in which there is a tendency for solidparticles to settle.

A copending application of ours, Ser. No. 464,982, filed June 28, 1965,deals with a slotted tray of the referred to type. The cap disclosed insaid copending application is provided with means depending from theunder- 3,445,095 Patented May 20, 1969 side of the cap and extendingdownwardly to or through the slot or slots in the tray, which is orwhich are covered by the cap. The depending means has side extensionswhich extend crosswise with respect to the depending means and arespaced from the underside of the tray so that such extensions may engagethe underside of the tray and thereby limit the upward movement of thecap when lifted by rising vapors and/or gases.

In the construction of the tray of the aforementioned copendingapplication, the depending means consists either of two parallel seriesof spaced members, with the members of one series being staggered withrespect to the members of the other series, or of a single series ofspaced members.

While in either of the two embodiments disclosed in our earlierapplication the depending means is constituted by individual spacedlyarranged members, the present in vention provides for each cap a singleelongated and continued depending member. Further, in either of thereferred to and previously disclosed two embodiments the dependingmembers are formed as integral parts of the main body of the cap itself,whereas the depending member of the present invention is formed as anadded part. Still further objects of our invention are, therefore, atray which can be provided with much narrower slots than heretofore, anda cap that, too, can be made much narrower and of light-weight materialand will nevertheless be elfective and rigid.

Additional objects of the invention will be apparent from the followingdescription.

Summary of the invention The invention provides, as appears indicatedhereinbefore, a single elongated and uninterrupted or continueddepending member rather than a series or two of individual spacedlyarranged depending members. The depending member according to theinvention is of a riblike formation and serves the purpose ofreinforcing the caps and of rendering a tray and its caps more efiicientand more economical.

Broadly, the invention consists in tray members having elongated slotsand in elongated caps, the latter being mounted to varyingly cover theslots. Each cap covers either a single slot or more than one slot, withsuch plurality of slots being longitudinally aligned, and isreciprocally movable relative to the area of the respective tray member,that surrounds the respective slot. Each of the caps includes oppositeside portions above the top of the respective tray member, a singleelongated and continued depending member, and abutment members. Thedepending member is centrally arranged on the underside of the cap toextend lengthwise and downwardly toward the slot underneath. Theabutment members are longitudinally spacedly secured to the dependingmember and limit the upward movement of the respective cap away from thereferred to tray area, when lifted by a rising vaporous and/or gaseousphase.

If a cap is to cover more than a single slot, it is, however, necessaryto divide the depending member accordingly. For instance, if a capcovers two longitudinally aligned slots, two separate aligned dependingmembers are provided. The spacing between the two members corresponds tothe end-to-end distance between the slots.

Brief description of the drawings Other features and many of theattendant advantages of the invention will readily be appreciated as thesame becomes better understood by reference to the detailed descriptionof preferred embodiments, following further below, when considered inconnection with the accompanying drawings in which:

FIG. 1 is a plan view of a slotted tray and of caps covering the slotsin the tray, the tray and caps embodying features of the invention, andthe tray being show in a fractionating column;

FIG. 2 shows two such trays one above the other, the slots and caps ofone of the trays appearing turned by 90 with respect to the slots andcaps of the other tray, the trays and caps being shown in cross sectionand a side view, respectively;

FIG. 3 is a fragmentary cross section, on an enlarged scale, of a tray,showing a single cap;

FIG. 4 is similar to FIG. 3, showing the cap in its lifted rather thanin its rest position;

FIG. 5 shows a modified cap in plan to enlarged scale;

FIG. 6 is a fragmentary oblique representation of a tray and cap ofFIGS. 1 to 4; and

FIG. 7 is a fragmentary cross section of a tray, showing anothermodified cap.

Description of preferred embodiments Referring to the drawings ingreater detail now, and initially to FIGS. 1 and 2, FIG. 1 shows aslotted tray 1 in a fractionating column 6, and FIG. 2 shows at asufficient distance from each other two adjacent trays 1 out of agreater number of trays now shown. In FIG. 1, the tray is shown to beprovided with seven slots which are designated 5 S S S S S S The slotsin one of the two trays of FIG. 2 and thus the caps 2 which cover theslots in said one tray appear angularly displaced with respect to theslots and caps of the other tray. The exemplary displacement shown inFIG. 2 is one of 90.

It is seen that the slots although of different lengths, are allelongated and that the caps 2 are of corresponding lengths.

Each cap 2 consists of an elongated cylindrically bent sheet strip,which is best seen in FIGS. 3 and 4, from the underside of which dependsa riblike member 3 that extends downwardly toward the slot underneath,and lengthwise substantially throughout the length of the respectivecap. Each rib or depending member supports a plurality of abutmentmembers 4. From FIG. 1 it will be seen that each of the two outermostcaps which cover the slots S S and each of the two caps next to theoutermost ones, which cover the slots S S has two abutment members 4,whereas the cap along the center line and the two caps to the left andright of the center cap, which cover the slots S S S have three abutmentmembers 4. The latter three caps are of identical length.

The abutment member 4 of FIGS. 1 to 6 is formed as a bifurcated flatbody having two lateral extensions 4 that form shoulders at 4" (seeespecially FIG. 3). The rib 3 is received between the two branches 4a,4a of the abutment member 4 and is fastened to the latter.

FIG. 3 shows a cap 2 in its rest position, with side portions 2 of thecap touching the top of the tray 1 and the lateral extensions 4' of theabutment member 4 being spaced from the underside of the tray.

The side portions 2' of each cap have along both of their edges spacedlyprovided cutouts C. The cutouts along one of the edges are, as can beseen from FIG. 1, staggered with respect to the cutouts along the otheredge. Each cutout is to serve as a passage P for liquid to trickletherethrough in downward direction (see FIG. 4).

When the caps are lifted by vapor or gas pressure, they may assume theuppermost position shown in FIG. 4. This position is determined by thedistance between the underside of the tray and the shoulders 4". In FIG.4, the two shoulders 4" are in actual contact with the underside of thetray. With the cap raised above the tray, there are passages P formedbetween the top of the tray and the side portions 2' of the cap.

As vapors and gases collect below the trays, they start lifting thecaps. First, vapors and gases escape along the ribs 3 and through narrowgaps between the top of the trays and the edges of the side portions 2',and as the caps rise more and more, the narrow gaps widen and form inthe end the Wide passages P. In FIG. 4, the flow of the liquid is shownin dashed lines, and the flow of the ascending phase in dotted lines.Liquid collected on the trays thus receives a turbulent movement, whichresults in an intimate contact of the two phases.

While the slots in the trays 1 have sharp-cornered ends, a slot Sa in atray 1a is shown in FIG. 5 as having an end 9 forming two rectangularcorners, and a rounded end 10. The cap 2a of FIG. 5 has both corneredcutouts 7 and rounded cutouts 8, rather than exclusively corneredcutouts like the cutouts C in FIGS. 1 to 4. Rounded slot ends such asthe end 10 and rounded cutouts such as the cutout 8 have an economicaleffect in lengthening the effective working periods of cutting tools.

In FIG. 7, a modified abutment member 5 is shown, which has, in additionto lateral extensions 5' that are to contact the tray 1 from below,lateral extensions 5a that lie on top of the tray when the abutmentmember is in its lowermost position. The extensions 5' act exactly asthe extensions 4' of the abutment members 4 of FIGS. 1 to 6, While theextensions 5a are effective in holding the cap 2 in its rest positionsuch distance away from the top of the tray 1 as will prevent the edgesof the side portions 2' to contact, and possibly stick to, the tray whenthe latter during operation becomes covered with sticky asphalticsubstances.

A d van rages It is believed that the construction and operation of thetray for practicing the invention, and the many advantages thereof, willbe fully understood from the foregoing detailed description. Some ofthese advantages are reviewed hereinafter. The construction of the capof the invention, which provides for the longitudinally extendingreinforcing rib, makes it possible to narrow substantially both theslots and caps and to achieve a more intimate and a more uniform contactover the whole of the surfaces of the trays. The reinforced capaccording to the invention permits relatively large cutouts along theedges of the side portions of the caps and does not require greatlifting heights for the caps. The gaseous and liquid phases are morefinely divided, which promotes heat and mass transfer. The cap is ofutmost simplicity, which reduces manufacturing, assembling, andmaintaining costs. The slotted tray and the cap of the invention are themost economical column equipment as yet developed for distillation,absorption, stripping, and similar purposes.

We claim:

1. In a fractionating column or the like for effecting intimate contactbetween a rising vaporous and/ or gaseous phase and a descending heavierliquid phase,

(a) slotted tray members, the slots in the tray members being elongated,

(b) elongated caps mounted to varyingly cover said slots, each of saidcaps having a longitudinal axis and a lower surface and beingreciprocally movable relative to the respective slot,

(c) a rib member associated with each of said caps, extendinglongitudinally, and uninterruptedly and substantially throughout thelength, of the respective cap, said rib member extending from said lowersurface toward the respective slot,

((1) abutment means provided on said rib member, said abutment meansbeing constituted by longitudinally spaced abutment members, portions ofeach of said abutment members being spaced from the underside of therespective tray member and being adapted to engage said underside and tolimit the upward movement of the respective cap.

2. The column according to claim 1, each of said abutment membersincluding a flat body extending substantially transversely of theelongation of the respective cap.

3. The column according to claim 1, each of said abutment membersincluding a bifurcated flat body having a pair of lateral extensions,portions of said rib member being received in the bifurcation of aplurality of abutment members.

4. The column according to claim 1, each of said abutment membersincluding a bifurcated fiat body having two spaced pairs of lateralextensions, portions of said rib member being received in thebifurcation of a plurality of abutment members.

5. The column according to claim 1, wherein each of said caps hasopposite side portions above the respective tray member and said sideportions have two longitudinally extending edges and spacedly arrangedcutouts along said edges.

6. The column according to claim 5, wherein the cutouts along one ofsaid edges are staggered with respect to the cutouts along the otheredge.

References Cited UNITED STATES PATENTS 9/1960 Nutter 261--114 5/1961 Eldet a1. 261114 FRANK W. LUTTER, Primary Examiner.

S. H. MARKOWITZ, Assistant Examiner.

US. Cl. X.R.

